This invention relates to an improved aerosol antiperspirant composition in the form of a substantially stable water-in-oil emulsion. More particularly, such improved antiperspirant compositions consist of a propellant and a base consisting essentially of a mixture of water and a water-soluble antiperspirant salt dispersed in a continuous phase containing an emollient-stabilizer agent and a water-in-oil emulsifier.
Antiperspirant compositions are well known and in wide use. Generally, such compositions employ compounds or complexes of aluminum as the active antiperspirant agent, and these compositions have been available in the form of a powder, a lotion, a cream, a liquid, a liquid spray and an aerosol. In recent years, the aerosol form has been very widely used, most commonly as anhydrous dispersions of particles of antiperspirant agents in an organic solvent-propellant liquid mixture. Solutions of antiperspirant agents in alcohol or alcohol/water propelled by a propellant produced wet sprays and were subject to severe container corrosion.
While each type of aerosol antiperspirant had its own particular problems and shortcomings, each type of aerosol utilized a chlorofluorohydrocarbon propellant because the resultant product was nonflammable. In fact, the flammable character of ethanol and hydrocarbon propellants tended to limit the use of these materials in aerosol antiperspirants. However, in view of the environmentalists' recent concern with the possible depletion of the ozone layer in the atmosphere which allegedly is related to the use of chlorofluorohydrocarbon propellants, a need exists to develop aerosol antiperspirants which do not employ such chlorinated propellants.
In order to fulfill the foregoing need, research again has been directed toward formulation of non-flammable aerosol antiperspirant compositions which preferably employ hydrocarbon propellant. One proposed product is the water-in-oil emulsion antiperspirant composition described in Canadian No. 1,076,030 wherein an aqueous solution of antiperspirant agent is dispersed in a liquid mixture of hydrocarbon propellant and an emollient oil. However, such compositions tend to lead an oily residue on the skin.